1. Field of the Invention
The present invention relates to image formation using an image sensor, and more particularly, to a method and an apparatus for an image processing apparatus which scans an image of an original document having a rectangular shape, line by line.
2. Description of the Related Art
In general, an image processing apparatus, such as an image scanner, facsimile, digital copier, or the like includes a central processing portion, an image sensor, an image reading portion, a memory portion, a computer interfacing portion, an information input/output portion and the like.
The central processing portion controls the overall operation of the above-mentioned devices. Particularly, the central processing portion stores image data acquired by the image sensor in the memory portion, and controls data conversion.
The image sensor emits light of a light source to an original document, and converts reflected light into an electrical output with a CCD (charge coupled device) and a CIS (contact image sensor).
The image reading portion causes an image converted into the electrical output to be stored in a data memory device such as a hard disk of a computer.
The memory portion stores image data transmitted from the image reading portion according to the control of the central processing portion, and stores other program data required for control operations of the central processing portion.
The computer interfacing portion acts as a path to transmit read image data to the computer.
The information input/output portion has a plurality of keys, applies data to the central processing portion when a predetermined key is selected, and displays operation status of the image processing apparatus controlled by the central processing portion.
However, a conventional image processing apparatus can process an image in a manner in which the size of an original document is sensed and the scanned image is equal to the sensed area of the original document. First, in the sensing of the size of the original document, after the periphery of the original document is exhibited clearly by lowering the resolution of the whole area of the image in a mode called a free scanning mode, information concerning the size of the original document is acquired. Subsequently, the size of the read image is the same as the size of the original document. The size of the original document is based on the information concerning the size of the original document while the resolution designated by a user is taken into consideration.
Therefore, in order to acquire an image in the conventional art, the image can be acquired after the scanning operation of the image is performed twice. Consequently, when a small document such as a business card or post card is copied, there is no way to scan the small document without preliminary free scanning, and when the free scanning is performed, the free scanning causes time consumption equal to the time required for the free scanning.